The 308 Marlin Express is a centerfire rifle cartridge standardised by SAAMI in ANSI/SAAMI Z299.4. SAAMI sets its maximum average pressure at 47,500 psi, and measures its reference velocities in a 24.000 in standard test barrel rifled 1 turn in 12.00 in. This guide sets out SAAMI’s published reference velocity for each bullet weight, computes the muzzle energy each one carries, and compares the 308 Marlin Express with the 30-30 Winchester on the same basis.
308 Marlin Express ballistics chart: SAAMI reference data
SAAMI publishes one nominal mean instrumental velocity for each reference bullet weight, measured at 15 feet from the standard test barrel. It does not publish energy, so the ft-lb column is computed. Where SAAMI lists more than one velocity for a weight, both ends of the span are shown.
Scroll the table sideways for the remaining columns.
| Bullet weight | Reference velocity | Computed muzzle energy |
|---|---|---|
| 140 gr | 2,800 fps | 2,437 ft-lb |
| 160 gr | 2,645 fps | 2,485 ft-lb |
What the numbers mean for a shot
SAAMI lists two reference bullet weights for the 308 Marlin Express, 140 and 160 grains. The lighter, 140 grains, is listed at 2,800 fps, which computes to 2,437 ft-lb. The heavier, 160 grains, is listed at 2,645 fps, which computes to 2,485 ft-lb.
None of this is a downrange figure. SAAMI measures at 15 feet, so retained velocity, energy and drop depend on the bullet’s ballistic coefficient, which SAAMI does not publish. Each product in our 308 Marlin Express ammo range lists whatever its maker publishes for that item.
Twist rate, chamber and pressure
SAAMI’s standard test barrel for the 308 Marlin Express is 24.000 in long and rifled 1 turn in 12.00 in, with a .308 in groove diameter. That is the barrel every reference velocity above was measured in, not a statement about your rifle: a shorter production barrel will usually give lower velocity, and a twist slower than a bullet needs will not stabilise it. The maximum average pressure is 47,500 psi. Fire 308 Marlin Express ammunition only in a firearm chambered for it. Several unrelated cartridges share a number, so match the full designation on the box to the marking on your barrel.
308 Marlin Express vs 30-30: the SAAMI comparison
A figure from one maker’s catalogue cannot be laid beside a figure from another’s: each picks its own test barrel, zero and bullet, and many publish no test barrel at all. SAAMI is the shared basis, because it fixes one standard test barrel and one way of measuring velocity for every cartridge it lists.
Scroll the table sideways for the remaining columns.
| SAAMI specification | 308 Marlin Express | 30-30 Winchester |
|---|---|---|
| Maximum average pressure | 47,500 psi | 42,000 psi |
| Standard test barrel length | 24.000 in | 24.000 in |
| Test barrel twist rate | 1 turn in 12.00 in | 1 turn in 12.00 in |
| Test barrel groove diameter | .308 in | .308 in |
| Lightest reference load | 140 gr — 2,800 fps / 2,437 ft-lb | 55 gr — 3,365 fps / 1,383 ft-lb |
| A weight both list | 160 gr — 2,645 fps / 2,485 ft-lb | 160 gr — 2,285–2,380 fps / 1,855–2,012 ft-lb |
| Heaviest reference load | 160 gr — 2,645 fps / 2,485 ft-lb | 175 gr — 1,050 fps / 428 ft-lb |
SAAMI standardises the 308 Marlin Express at 47,500 psi and the 30-30 Winchester at 42,000 psi, so the 308 Marlin Express runs 5,500 psi higher. At 160 grains, a weight both list, SAAMI’s 308 Marlin Express reference velocity is 2,645 fps (2,485 ft-lb computed), against up to 2,380 fps (2,012 ft-lb) for the 30-30 Winchester. On that row the 308 Marlin Express carries the more energy.
What SAAMI cannot settle is anything past the muzzle. It publishes no ballistic coefficients and no downrange data, so it cannot say which cartridge shoots flatter at distance; that depends on the bullet. We stock the other side of this comparison too: 30-30 ammo.
308 Marlin Express ballistics questions
What is the maximum pressure of the 308 Marlin Express?
ANSI/SAAMI Z299.4 sets the maximum average pressure for the 308 Marlin Express at 47,500 psi.
What twist rate and barrel length does SAAMI use for the 308 Marlin Express?
SAAMI’s standard test barrel for the 308 Marlin Express is 24.000 in long and rifled 1 turn in 12.00 in. Your own rifle may differ.
What bullet weights does SAAMI list for the 308 Marlin Express?
SAAMI lists 2 reference weights, from 140 to 160 grains: 140 and 160.
Is the 308 Marlin Express more powerful than the 30-30 Winchester?
Power is not a SAAMI measure, but reference muzzle energy is a fair proxy. At 160 grains, a weight both list, SAAMI’s 308 Marlin Express reference velocity is 2,645 fps (2,485 ft-lb computed), against up to 2,380 fps (2,012 ft-lb) for the 30-30 Winchester.
What is the effective range of the 308 Marlin Express?
Effective range is not a SAAMI specification and it is not a measured figure. SAAMI measures velocity at 15 feet, so it says nothing about performance at distance; that depends on the bullet and the shooter.
How much does the 308 Marlin Express drop at 300 yards?
SAAMI publishes muzzle velocity only, so it cannot give a drop figure. Drop depends on the bullet’s ballistic coefficient and on the zero range. A drop figure is unusable without its zero, so use the figure a maker prints for the specific load.
Where to buy these loads
Hilltop Armory carries 308 Marlin Express ammunition from Hornady and Remington. Browse the full 308 Marlin Express ammo range.
